This is one of my favorites of yours...a 'normal' looking webbed hand! I hope you do a webbed foot like that sometime, too. The only improvement I can suggest is to make the webbing appear to blend more smoothly to the sides of the fingers by eliminating the hard outlines of the fingers. These examples show that:
http://www.furaffinity.net/view/8366715/
http://sandcastler.deviantart.com/f.....514111#/d4vnl6
http://www.furaffinity.net/view/8233776/

I really love your mermaid work and always look forward to new pieces!!